A teenage student has become the latest victim in Dallas to die from a powerful and highly addictive new street drug known as 'cheese'. The rise of the drug, a mixture of black tar heroin and powdered headache tablets, has been described as an epidemic. Dealers often sell it at $2 a time to get youngsters hooked. Because it is snorted, teenagers do not realise they are taking such a lethal heroin-based drug.

Since 2005 at least 23 teenagers in the Texan city have died after taking cheese, so called because it resembles crumbled Parmesan. The latest victim was 18-year-old Scott Clark, a volunteer for a local animal charity and a fitness fanatic.

The drug is mass produced in Mexico and smuggled across the border in increasing quantities. The authorities are so concerned that a special regional 'cheese task force' has been set up to tackle the problem.

Sergeant Jeremy Liebbe said: 'To market heroin to kids, you've got to get rid of the needle because even the hardcore cheese users that we've identified and brought into custody have said "I wouldn't stick a needle in me to get high, but I'll snort it up my nose".

The deaths have been almost split 50-50 between Hispanic and white youths. The vast majority of the victims have been boys. Only two girls have died from the drug.

Zachary Thompson, director of Dallas County Health and Human Services, said: 'We've had this drug in the community for some time and didn't recognise it at first. Cheese heroin has been the most instantly addictive and deadliest drug that we have seen since the crack cocaine epidemic.'